Manufacture of hollow plastic articles



Aug. 18, 1964 R. HAGEN 3,145,243

MANUFACTURE OF HOLLOW PLASTIC ARTICLES Filed Sept. 8. 1961 5Sheets-Sheet 1 25 29 30 Fig-7 I7 I 2 I4 56 25d 2 29 30 INVENTOR [Fe #1a/a zf a ew WMQ Aug. 18, 1964 R. HAGEN 3,145,243

MANUFACTURE OF HOLLOW PLASTIC ARTICLES Filed Sept. 8, 1961 5Sheets-Sheet 2 Fig.

Fig. 15

IN VE N TOP ?e /'/7 a/a 6 6560 Aug. 18, 1964 R. HAGEN 3,145,243

MANUFACTURE OF HOLLOW PLASTIC ARTICLES Filed Sept. 8, 1361 5Sheets-Sheet (5 Aug. 18, 1964 R; HAGEN 3,145,243 7 MANUFACTURE OF HOLLOWPLASTIC ARTICLES Filed Sept. 8. 1961 5 Sheets-Sheet 4 251: 253 Fig.24 6.29

INVENTOR z e/na/q f/crye/r BY Aug. 18, 1964 R HAGEN 3,145,243

MANUFACTURE OF HOLLOW PLASTIC ARTICLES Filed Sept. 8, 1961 5Sheets-Sheet 5 &

67a Fig.3! 06' INVENTOP 6/ 0/4 4907 %QM W/ United States Patent3,145,243 MANUFACTURE OF HOLLOW PLASTIC ARTICLES Reinold Hagen, Hangelaruber Siegburg,

eland, Germany Filed Sept. 8, 1961, Ser. No. 136,846 Slaims priority,application Germany Sept. 12, 1%0

I Claims. (Cl. 264-98) This invention relates to the manufacture ofhollow articles from plastics, and more particularly to a process and anapparatus for blowing such articles. Whenever this specification and theappended claims speak of bottles, such term is understood to comprisehollow bodies of any shape, provided the shape of an embryo article,while in condition of plasticity, permits its being blown by fluidpressure into molding contact with a mold cavitydefining wall and thusto the desired final shape.

For the purpose of the invention, any plastic material may be used whichis capable of becoming softened and workable when heated at relativelylow temperatures and which, while soft and workable, may be expandedunder fluid pressure into desired shapes. The blown articles, uponcooling, become rigid. For instance, low, medium and high densitypolyethylene, polystyrene, plasticized and nonplasticized polyvinylchloride and nylon may be used.

The primary object of the present invention is to generally improve themanufacture of hollow plastic articles by blowing.

In producing bottles, other containers, and other hollow articles fromplastics, for instance, by blow-molding, articles are obtained whichhave waste material adhering thereto that must be removed. So far, suchremoval has been done by hand. Each article, upon its ejection from themold, has to be picked up by hand so that any waste can be removed byhand. This hand-operation is slow and expensive. An importantobject ofthis invention is, therefore, to provide an apparatus which will removeall Waste clinging to a blow-molded article automatically. Thus, myinvention aims at speeding up and cheapening the manufacture of hollowplastic articles. The waste material here involved is ordinarilyreferred to as flashing.

Another important object of the invention is to provide a waste-removingor flashing-tearing device the provision and operation of which does notinterfere either with blowmolding equipment or blow-molding cycles. Thewasteremoval does not collide with the blow-molding equipment, and theoperation of the waste-removing device falls within the usual sequenceof operations of the blow-molding cycle.

The automatic waste-removal according to the invention is directed atwaste in whatever location it may appear. In blow-molding, waste formsat places where the preform used is pinched by closing mold sections.If, for instance, a bottle or another container having a necklikeformation is produced, waste usually appears at the bottom and neck ofthe bottle or container. The present invention provides that waste inall possible locations be torn off from the blown article independentlyfrom the mold equipment.

Other objects of the invention center about a process and an apparatusfor the removal of plastic waste, which are easily adaptable to varyingconstructions of blowmolding equipment and thus to varying conditions.

One object of the invention is to provide a waste-re moving orwaste-stripping device, which is simple, of relatively small dimensions,inexpensive, and economical in operation.

Further objects will be apparent from the following description.

3,145,243 Patented Aug. 18, 1964 The specification is accompanied bydrawings in which:

FIGS. 1 to 6 show, in side elevational views, partly sectioned, anapparatus for the manufacture of bottles by blowing, the apparatusembodying a waste-removing device according to my invention, the sixviews illustrating different positions of parts of the apparatus anddifferent operational conditions;

FIGS. 7 to 9 are bottom views of the waste-removing device of theapparatus as shown in FIGS. 4 to 6;

FIG. 10 is a section taken in the plane of the line 1010 of FIG. 2;

FIG. 11 is a detail of the view of FIG. 5, drawn to enlarged scale;

FIG. 12 is a plan view of the showing of FIG. 11;

FIG. 13 is a view similar to that of FIG. 12 but illustrating adifierent operational condition;

FIG. 14 is a vertical section taken in the plane of the line 1414 ofFIG. 11;

FIG. 15 is a section taken in the plane of the line 15-15 of FIG. 13;

FIG. 16 is a section taken in the plane of the line 1616 of FIG. 13;

FIGS. 17 and 18 illustrate a modified waste-removing device in twodiiierent stages of operation; 7

FIGS. 19 and 20 show in two elevational views another modification ofthe waste-removing device of the invention;

FIG. 21 is a schematic view of a further modification;

FIGS. 22 to 24 illustrate, in an elevational, elevational, and planview, respectively, the modification of FIG. 21;

FIGS. 25 to 27 are elevational views of a fifth modification of mywaste-removing device;

FIGS. 28 and 29 illustrate a sixth modification;

FIGS. 30 and 31 illustrate a seventh modification; and

FIGS. 32 to 34 are explanatory of a certain mode of removal of wastefrom the bottom of a bottle.

Referring to the drawings in greater detail, and initially to FIGS. 1 to16, an extrusion nozzle 10 of an extruder 11 has an annular outletorifice to extrude the plastic material used in form of a tube. As soonas an adequate length of tubing has been extruded, and while the tubingis still in a condition of plasticity, a two-part grasping or grippingdevice 13, adapted to be closed and opened, closes and severs a tubelength 12 from its parent body and carries this length verticallydownward into the space between two open sections 14, 14' of a mold. Theleading end 12' of the tube 12 is open and slips over a blow pipe 15which extends into the open mold space from opposite the extrusionnozzle and is axially aligned with the downwardly moving tube. When thetube 12, has reached a position in which it extends beyond the upper andlower edges of the mold, with the grasping device 13 remaining outsidethe mold, the mold sections are closed upon the tube to assume theposition shown in FIG. 2 and to convert thereby the tube into a bubble(not shown) closed at the top and open at the bottom. As the moldcloses, an end portion 12a of the tube 12 is pinched off, while at theother end of the tube an end portion is press-molded against the blowpipe 15.

When working according to known processes or with the aid of knownequipment, waste, such as the portion 12a clings to the bottom of thearticle formed at 18 (see FIG. 2) and is ordinarily removed by hand.Such trimming requires that every single article formed has to be pickedup by hand. My present invention provides that waste, such as the endportion 12a, as well as waste in any other place is automaticallyremoved rather than by hand. According to the present invention, theclosed grasping device 13 continues to hold the portion 12a during theclosing of the mold but moves upwardly, im-

, mediately upon the closing of the mold, In the direction amazes of thearrow 19 and thereby separates the portion 12a from the bottle bytearing it off.

While the grasping device moves upwardly, a new length 12b of tubing isbeing extruded. FIGS. 2, 3, 4, and 6 show how this new length graduallyincreases. The grasping device 13 is shown in FIG. 2 in closed orgrasping condition and on its upward way, and in FIGS. 3 to 6 it isshown in open condition and at its upper level. In the situation shownin FIG. 6, when the length 121) has reached the length of the tube 12,shown in FIG. 1, the grasping device closes about the new tube length12b to separate it from the parent plastic material in the nozzle and totransport it downwardly into the open mold space.

It usually happens that a blown article has waste cling thereto in morethan one place. A blownbottle 26 as shown in FIGS. 2 to 5 and 11,although free of waste material at its bottom, has waste materialadhering thereto at its neck 16. Such additional waste material is bestshown in FIG. 14. It has the form of two fins 22 appearing on theshoulder 21 of the bottle and on opposite sides of the neck 16 and of anannular body 23 appearing on the neck and between the fins. From the waythe fins 22 form, when the mold closes, it will be clear that theyextend on opposite sides of the neck across a plane that coincides withthe parting plane of the mold. The annular body 23 is a sort ofextension of the bottle neck and is connected with the same at 24. Thefins 22 and the annular extension 23 are connected to each other and tothe main body of the bottle, that is, to the shoulder 21 and neck 16, bymeans of thin webs which so far have been torn off by hand. Such websform due to the fact that the cutting edges of the mold sections pinchopposing material thicknesses strongly together without actuallycutting.

My invention provides that for the purpose of automatically removingwaste material, such as the fins 22 and the annular extension 23, thebottle 20, while still supported by the blow pipe 15, is, upon theopening of the mold, moved downwardly, that is, below the level of themold 14. In FIG. 3, the bottle 20 is shown at the level of the mold,whereas in FIGS. 4 to 6 it is shown at a level lower than that of themold. The bottle is moved downwardly by moving the blow pipe downwardly.This downward movement brings the bottle in reach of a device 25 (seeFIG. 4) which separates both the fins 22 and the annular extension 23from the bottle. This device consists of two cooperating members 25a and25b which are mounted to be moved in the directions of the arrows 27 and28 from the open position shown in FIGS. 1 to 4 and 7 toward each otherinto the closed position shown in FIGS. 5, 8, 11 and 12.

The members 25a and 25b are of forklike configuration so that the tines25d of the member 25a and the tines 25c of the member 25b, in the closedcondition of the device 25, shown, for instance, in FIGS. 5 and 8, mayreceive the blow pipe 15 and the neck 16 of the bottle 20 carried by theblow pipe. As can be seen from FIG. 11, the members a and 251) are ofrelatively thin section, when viewed vertically, in order not to behigher than the length of the bottle neck 16 and thus to permit beingmoved underneath the shoulder 21 of the bottle. It will be appreciatedthat shape and dimensions of the members 25a, 25b depend on thecircumstances in every case, such as the shape of the article to befreed of waste material, and the formation of waste material.

Since the fins 22, as has been indicated, extend in the parting plane ofthe mold, they are substantially parallel to the frontal faces 29, ofthe members 25a and 2511, respectively (see FIG. 7). The closing andopening movements of the members 25a, 2512 are perpendicular to theparting plane. To close the device 25 its members are moved toward eachother until the frontal faces 29, 30 engage the fins on opposite sides,as can be seen from FIGS. 5, 8, l1 and 12. After such engagement hastaken place, a relative motion between the bottle 20 and the blow pipe15, on the one hand, and the members 25a, 25b, on the other hand, iseffected. If blow pipe and bottle stand still, the members 25a, 25b aremoved to the left, that is, from the position shown in FIGS. 5, 8, 11and 12 into the position of FIGS. 6 ,9 and 13. While the bottle which issupported by the blow pipe stands still, the fins 22 clamped between thefrontal faces 29, 30 of the members 25a, 25b participate in the referredto relative movement and are separated from the neck 16 and shoulder 21of the bottle, which can clearly be seen from FIGS. 6, 9 and 13.

From FIGS. 5, 8, 11 and 12 it will be seen that the two members 25a and25b first move toward each other so that the frontal faces 29, 30 engagethe fins 22 on both sides. The tines 25d of the right-hand member 25abeing longer than the tines 25c of the left-hand member 25b, as can beseen, for instance, from FIGS. 1 to 9, the members 25a, 25b, with thefins 22 sandwiched between them, may be moved to the left until the neck16 is received in the bed 17 of the long slot 17'. If a member like theone designated 25a, with long tines and a long slot, is provided on theleft-hand side, and if the member having short tines and acorrespondingly short slot is provided on the right, the two memberswith waste material between them would have to move to the right.

FIG. 15 shows the plastic waste in separated condition. It consists ofthe fins 22 and the annular extension 23. The webs which connect thefins 22 to the shoulder 21 and neck 16 (see FIG. 14) are thin and extendin a single plane. They are easily severed or torn off by a force whichacts in a direction perpendicularly to the extent of the fins, as isexerted by the movement of the members 25a, 25b. The extension 23 of thebottle neck being annular, the web which connects this extension to thefrontal face of the neck is of circular shape. To make it possible forthe annular extension, when exposed to the pressure exerted by themembers 25a, 251) against the fins 22, to clear the blow pipe 15, theextension is provided with a notch 31 as shown, for instance, in FIG.10. This notch extends substantially from the frontal face of the neck16 at 24 (FIG. 15 to the free edge 32 of the extension. The notch 31which weakens or actually splits the material of the extension 23 isproduced during forming of the article in the mold 14. For this purpose,the mold half 14 is provided, as can again be seen from FIG. 10, with awedgelike formation 33 which projects into the annular space defined bythe blow pipe 15 and the mold halves 14, 14'. It will be appreciatedthat the projection 33 is provided along the vertical extent of theextension 23 and is formed during the closing of the mold since the neck16 as well as the extension 23 are formed by pressmolding, as has beenstated hereinbefore (see FIGS. 14 and 15 The notch 31 makes it possiblefor the annular extension 23 to be easily removed from the neck 16,together with the fins 22, when the members 25a, 25b move relative tothe blow pipe 15 and bottle 20 and take the fins sandwiched between themembers 25a, 25b along. The annular extension bursts open along thenotch 31 so that the end portions 34 (see FIG. 15) of what has been theclosed annular extension before may be moved past the blow pipe 15, theplastic material of the open annulus being elastic and permitting theend portions 34 to be spread to allow the blow pipe to move out of thenow open enclosure.

FIGS. 6, 9, 13 and 16 show the bottle 20 freed of the fins 22 and theannular extension 23, in which condition the bottle may be withdrawnfrom the blow pipe 15 in any suitable way.

It is to be understood that while an article is blown, the blownarticle, upon opening of the mold, is lowered, and the article is freedof waste material, the extrusion continues. When a finished article iswithdraw or ejected from a blow pipe, 21 new length of freshly extrudedtubing is moved downwardly into the open space of the mold, as has beenexplained hereinbefore, while at the same time the blow pipe is raisedto have the leading end of the fresh tube length slip over the free endportion of the blow pipe. The downward movement of the blown article,upon the opening of the mold, makes it possible for the article to bemechanically freed from the waste material clinging thereto and frombeing withdrawn from the blow pipe without interfering with continuousextrusion and freshly extruded tubing.

The operations of closing the mold upon a length of tube, blowing thehollow article, opening the mold, lowering the blow pipe and blownarticle, trimming the article of its waste material, ejecting thefinished article, raising the blow pipe, etc. are automaticallycontrolled in a predetermined sequence and are adjusted to the rate ofextrusion, whereby the time needed for cooling the blown article is alsotaken into consideration. For instance, if due to a slower rate ofextrusion and/ or a shorter cooling and solidifying period, there is nointerference with freshly extruded tubing when a finished article isremoved from a blow pipe even though the waste-removing device of theinvention is arranged at a higher level as shown in FIGS. 1 to 6, say,immediately below the mold, there is, of course, no objection toproviding the waste-removing device at a suitable higher level.

In FIGS. 1 to 16, two waste-removing devices are shown, the grippingdevice 13 and the device 25. The former is generally operated byclosing, lowering, raising, and opening, and the latter is generallyoperated by closing, laterally moving, laterally returning, and opening.It is to be understood that these fourfold motions need not be cleanlyseparated. For instance, the device 13 may be raised while it opens. Anysuitable means may be used to actuate the two devices.

While according to the construction of FIGS. 1 to 16, the complementarymembers 25a, 25b of the waste-removing device 25 are operated in thesame directions as are the mold sections, that is, perpendicularly tothe parting surface of the mold, the construction of FIGS. 17 and 18requires the waste-removing device 25' to be operated perpendicularly tothe closing and opening directions of the mold or parallel to theparting surface of the mold, that is, in the directions of arrows 35,36. In FIG. 17, a bottle 20 is shown to be supported by a blow pipe 15.Also indicated are fins 22 which extend in the same direction as do thefins shown, for instance, in FIG. 7, namely, parallel to the partingplane of the mold. As distinguished from the construction dealt with inFIGS. 1 to 16, the construction of FIGS. 17 and 18 includes a blow pipewhich is rotatable about its longitudinal axis in the direction of thearrow 37. In FIG. 18, the blow pipe 15' appears turned through 90", andas the blow pipe turns, the article supported by it and the fins 22 alsoturn. The turned fins are shown to extend perpendicularly to the partingplane of the mold and to be ready to be acted upon by the members 25a,25b. The latter are constructed and operated as has been shown anddescribed with respect to FIGS. 1 to 16. The fins and the annularextension of the bottle neck are removed as has likewise been explained.

The blow pipe 15' may be mounted to be lowered and raised as in theconstruction of FIGS. 1 to 16 but it need not be lowered as in the caseof the construction of FIGS. 1 to 16 to permit the operation of thewaste-removing device. In the construction of FIGS. 1 to 16, the blownarticle has to be lowered to make the operation of the waste-removingdevice possible since the mold and wasteremoving device would otherwiseinterfere with each other. In the construction of FIGS. 17 and 18, themembers 25a, 2511 can be operated at the level of the mold withoutinterference since they can freely be moved at any level of the heightof the open mold space.

The construction of FIGS. 19 and 20 provides a plurality of blow pipesto cooperate with a single mold. From FIG. 20 it can be seen that fourblow pipes 15" are crosswise arranged to be turned about a center 38 sothat at any one time one of the blow pipes enters the mold 14, 14 whileanother blow pipe enters a waste removing station to cooperate with thewaste-removing device 25". When working with the construction of FIGS.19 and 20 and an article has been blow-formed in the mold 14, 14', themold is opened and the cross of blow pipes is turned through in thedirection of the arrow 39. The blown article is carried by therespective blow pipe to the waste removing station to be trimmed ofwaste material. When a blow pipe moves from position a to position b,the blow pipe from position b moves to position 0, blow pipe fromposition c moves to position a, and the blow pipe from position 0! movesto position a. In the b-position or wasteremoving station, the device25" acts upon fins on the blown article, whereby the fins and a possibleannular extension are separated from the bottle 20. During theseparation of waste material in position b, a new article is formed inposition a, and as the newly formed article, upon the opening of themold, is moved to position b, the article that has been finished in theposition b is moved into position c. The finished article is removedeither in position 0 or d.

It will be apparent that the waste-removing device need not be inposition b, that is, adjacent the mold, but may be provided either inposition 0 or a. The arrangement will depend on the existingcircumstances. If, for instance, a longer cooling period is needed priorto the wasteremoving operation, then the waste-removing device is notprovided in position b, but in position 0 or d.

The construction of FIGS. 21 to 24 includes for the use of a single moldtwo blow pipes 15 and 15 and two waste-removing devices 25 and 25 Thewaste-removing devices are arranged on opposite side of the mold, withthe two members of each of these devices being movable in the samedirections as the mold sections. The blow pipes are reciprocatinglymovable in the parting plane of the mold and are spaced from each otherso that when one of the blow pipes extends into the open mold space or,is within the closed mold the other blow pipe is in one of the twowaste-removing stations. In FIG. 21, the blown unfinished article isshown to be ready to be finished by means of the waste-removing device25 FIG. 21 shows the blow pipe 15 and the bottle 20 which is supportedby blow pipe 15 in the station of the waste-removing device 25;, outsidethe mold 114, 14. The blow pipe 15 is shown to extend into the open moldspace. The bottle is freed from plastic waste by the cooperating members25a 25b of the device 25 as has been explained before. While theseparation of the waste takes place and the finished bottle is removedfrom the blow pipe 15 a new length of tubing is extruded over the blowpipe 15 and the mold is closed upon the freshly extruded tubing and,upon blowing, again opened. Then, the blow pipes 15 and 15 which arepreferably carried by a common support 42 (see FIGS. 22 to 24) are slidin the direction toward the station of the waste-removing device 25until the blow pipe lfi assumes the position within the open mold space,previously assumed by blow pipe 15 and the blow pipe 15 carrying a newlyblown unfinished bottle reaches the position 15 shown in a broken line.Next, freshly extruded tube is received by blow pipe 15 while the lastproduced unfinished bottle 1s finished in the station of the device 25Thus, in the embodiment selected for illustration in FIGS. 21 to 24, theblow pipe 15 cooperates with the device 25 whereas the blow pipe 15cooperates with the device 25 Aside from the time needed for themovements of the blow pipes, while one of the blow pipes is in the moldthe other blow pipe is in one of the two waste-removing stations.Details of the construction of FIGS. 21 to 24 and their structuralrelationship are shown in FIGS. 22 to 24.

The construction and operation of the mechanism to raise and lower andto open and close the grasping or gripping device is as follows: Themold 14, 14' is spaced- 1y mounted with respect to the annular extrusionnozzle 45. A gripping device 13 consisting of two parts 13:! and 13bsevers a length of tubing from the parent body of plastic material nearthe bottom of the extrusion nozzle and carries the tube length thussevered downwardly. In FIGS. 22 and 23, the grasping device is shown atits lowest level. Provisions may, of course, be made that the severingis done in such a way that the leading end of the parent tube from whicha tube length has been severed will stay open after severing. Theraising and lowering of the grasping device 13 is effected overcylinders 47 and 48 which are supported, as is shown in FIG. 22, by theextruder 11. Slidingly accommodated in these cylinders arefluid-operated pistons 4'59 and 59 to reciprocate in the same directionat any one time. At the free ends of these pistons, cylinders 51, 52 and53, 54 are mounted for reciprocation whereas the pistons in thesecylinders are stationary. The cylinders 51, 52, 53 and 54 are connectedto arms 55, 56 and 57, 58 which carry the parts 13a, 13b of the graspingdevice 13 at their lower ends. The opening and closing of the graspingdevice is effected by the cylinders 51, 52, 53, 54 over the arms 55, 56,57, 58. After the closing of the mold upon a tube length that has beentransported by the closed grasping device downwardly into the open moldspace, the closed grasping device is returned upwardly with the aid ofthe cylinders 47, 48, whereby, as has been described with reference toFIG. 2, waste material 12a tears off from the bottom of the bottle andis taken along by the grasping device during its upward travel. Beforethe grasping device reaches its uppermost level, it opens. This openingis done by the cylinders 51, 52, 53, 54 which by means of the arms 55,56, 57, 58 cause the parts 13a. and 13b of the grasping device to moveapart. The waste material 12a drops from the grasping device. Variousmeans may be provided to transport the waste material away when it hasdropped. The grasping device reaches its uppermost position in opencondition. This is necessary so that any interference with freshlyextruded tubing is avoided. As soon as fresh tubing has been extruded inadequate length, the grasping device grips the tube length at its upperend, at the extrusion nozzle 45, severs the tube length from theextrusion nozzle, and transports the severed length downwardly for theblowing of the next article to be produced. The two waste-removingdevices 25 are operated as follows: Upon closing of the mold and theinflation of a tube length within the mold, with the infiated bottlebeing supported by the blow pipe 15 and upon opening of the mold, theblow pipe 15 supporting the freshly blown and sufiiciently solidifiedbottle moves across the parting plane of the mold to the station of thewaste-removing device 25 to be stripped thereof the waste material stilladhering to the bottle. When the blow pipe 15 was ready to be moved toposition 15 or the position of the device 25 or to the left in FIG. 23,the bottle in the position of the waste-removing device 25 had beenfreed of waste material and ejected from the blow pipe 15 allowing theblow pipe 15 to move into the open mold space. The support 42hereinbefore referred to is mounted to slide on a rail 59. This slidingmotion is controlled by a piston accommodated in a cylinder 60. Uponremoval of waste material in the station of the device 25 the bottlefreed from such material is removed from the blow pipe 15 and the lattermoves to the right (FIG. 23) back into the open mold space, while anewly formed bottle carried by the blow pipe 15 also moves to the rightto be finished by the device 25 The devices 25 and 25 are opened andclosed by means of hydraulic or pneumatic cylinders 65, 66 and 63, 64,respectively. It should be noted that the bars 67 and 68 which carry thedevice 25 and 25 respectively, are adjustable so that the devices can beused in different heights depending on the shape and dimensions of thearticles to be produced. For similar reasons, each of the devices 25 and25 is exchangeable to be adapted 8 to the snape of the particularplastic to be removed. From FIGS. 22 and 24 it can be seen that thefrontal faces 29 and 38 of the devices 25 and 25 are fiat to ensureproper engagement of the fins 22.

Reference is made to a copending application of mine, Serial No.120,828, filed May 16, 1961, which deals with the shortening of thecooling time of freshly blown plastic articles and the withdrawing ofsuch articles from a mold when solidified to a self-supporting state.Among other embodiments, said copending application is concerned with aconstruction using a mold and two blow pipes, with the blow pipes beingsimilarly arranged as in the construction of the present FIGS. 21 to 24.

Each of the devices 25 and 25 is equipped with a pair of cylinders 63,64 and 65, 66, respectively. The cylinders 65, 66 first move the parts25:1 and 25b toward each other to engage thereby the fins 22 on oppositesides, and then they move to effect the movement relative to the bottleheld by the blow pipe 15 The cylinders 63, 64 act similarly in thestation of the waste-removing device 25 In the embodiments shown, thebottle is supported by a blow pipe and is stationary whereas thewaste-removing devices are movable. It will, however, be appreciatedthat this relative motion can also be effected by holding thewaste-removing devices stationary and moving the bottle instead. In theembodiment of FIGS. 21 to 24, FIGS. 21, 22 and 24 show that thewaste-removing device 2511 has to be moved to the left to effect thewaste removal. From these three figures it is clear that the tines ofthe device 25:1 are longer than those of the device 25b; and that it isthe device 25 that can be moved to the left before the blow pipe and thebottle supported by the blow pipe strike against the crosspiece of thepart 250 at 69 (see FIG. 24). Similarly, it is the part 25:1 which haslonger tines than the part 25b that is moved relative to the bottle tobe stripped from waste.

In order to cause the movement of the parts 25(1 and 25:2 to the left,after the two complementary parts have been brought into engagement,with the fins between them, it is possible to increase the pressure inthe cylinders 64 and 66. Thus, the force exerted, for instance, by thecylinder 66 upon the part 25% which according to FIG. 24 is to be movedto the left will be greater than the force exerted by the cylinder uponthe part 25b and this will result in a shift of both devices 25:1 and2512 to the left. Another way of causing the movement of the devices2511 2511 and 25:1 25b;, to the left may be that the cylinders 66 and 64are given a larger diameter than the cylinders 65, 63 so that with thesame pressure in the cylinders 64, 66 and 63, 65 respectively, a shiftto the left will result, this being due to the larger crosswiseextending surfaces of the cylinders 66, 64. Still another possibility ofeffecting the move to the left consists in using spring means instead ofthe cylinders 63, 65, which spring means would serve to bring thedevices 25b 2517;, into engagement with the fins and the opposingdevices 250 25:1 whereupon the movement to the left would be caused bythe cylinders 64, 66 acting against the force of the spring means. Itwill be understood, regardless of the principle employment to cause therelative movement, that the tines of one of the waste-removing partshave a length at least equal to the distance the Waste has to beshifted.

One way of removing the waste material 120 from a blown bottle, and moreparticularly from the bottom of a bottle, by means of a grasping device13 has been shown in and explained with reference to FIGS. 1 to 6 and 22to 24. FIGS. 25 to 27 show another way of removing such waste from thebottom of a bottle. The manner shown in FIGS. 25 to 27 is resorted toespecially when for some reason no grasping device is used to sever alength of tubing and to transport the severed length. However, the wayto be described presently may be used even if a grasping device ispresent. Essentially, the device of PLUS. 25 to 27 consists of two jaws70a, 70b besides two members 25a, 25b (see FIGS. 1 to 16). The jaws 70a,7% or similar clamping members are mounted to move from a starting oropen position (FIG. 25) into a closed position shown in FIG. 26, wherebythe frontal faces 71a and 71b of the jaws 70a and 70b engage wastematerial 12a on the bottom of the blown bottle 20. Then, the jaws 711a,7% are moved relative to the blow pipe 15 and the bottle carried by theblow pipe in a fashion and by means as has been described hereinbeforewith respect to the device 25. It is due to this lateral movement thatthe waste material 12a is torn off the bottom of the bottle. In theconstruction of FIGS. 25 to 27, the jaws 70a, 79b are carried bysupports 72 secured to the members 25a, 25b. The jaws 70a, 70b andmembers 25a and 25b are simultaneously actuated by the same actuatingmeans. The members 25a, 2512 may be connected to hydraulic or pneumaticcylinders. It should be understood that the supports 72 are adjustablein length, making it possible that the total mechanism 25a and 25b, 72,70a, 7012 can readily be adapted to articles of different heights whichare to be finished. It is further to be understood that instead of thejaws 7 a, 7012 a device may be provided, the members of which are likeor resemble those designated 25a, 2512. This possibility will bepreferred, for instance, if the article to be finished has two necklikeformations on opposite sides.

To prevent waste material separated from a bottle from dropping in anuncontrolled manner, it is possible to provide at least one of themembers 25a, 25b and/or one of the jaws 70a, 7% with a bore or boreswhich terminate in a respective frontal face and to connect said bore orbores with a source of vacuum. Such arrangement is shown in FIG. 12 andhas the purpose to suck the waste material to the frontal face and tohold it there. In FIG. 12, the member 25b is shown to be provided withtwo passages 73 which terminate in the frontal faces 29 of the tines 25cand communicate with a bore 74- which is connected to a source ofvacuum. With the bore 74 and the passages 73 under vacuum, separatedwaste material is held onto the frontal faces 29 of the part 25b. Onlywhen the vacuum is released is the waste material held by the member 25bfree to drop.

FIGS. 28 and 29 show a modification according to which fins 22 areengaged and gripped by jaws 75a, 75b and 76a, 76b. Such jaws form, forinstance, the terminal parts of tonglike devices. As distinguished fromthe cases described so far, the fins 22 and annular extension 23 are notremoved due to movements in directions perpendicularly to the extent ofthe fins 22 but in the directions of that extent of the arrows 77 and78- The jaws 75a, 75b and 7a, 7612, after they have engaged the fins 22,as shown in FIG. 28, are pulled away from the bottle and blow pipe inthe directions of the arrows 77 and 78 until they reach the positionshown in FIG. 29. From FIG. 28 it will be clear that the annular ring 23has been molded to have two notches 31, 31 and FIG. 29 shows that thepulling apart action of the two pairs of jaws, as provided in theconstruction of FIGS. 28 and 29, due to the provision of two notches,splits the annular extension into two semi-annular parts. In connectionwith the description of FIG. 10, it has been explained that one of themold sections has a projecting wedge 33 which forms the notch 31 in theannular extension 23. In the construction of FIGS. 28 and 29, each ofthe two opposing mold halves has a wedge formation to form a notch 31.The device of FIGS. 28 and 29 may be used in combination with anyone ofthe constructions hereinbefore dealt with. For instance, it may take theplace of the device 25 of the construction of FIGS. 1 to 16 and be usedtogether with the grasping or gripping device 13. It may replace thedevice 25 of the construction of FIGS. 17 and 18, the device 25 of FIGS.19 and 20, and the device 25 25 of FIGS. 21 to 24, respectively.

In the construction of FIGS. 30 and 31, there are two slides 82, 82which are movable in the directions of the arrows 811, 81. These slidesmay be connected to hydraulic or pneumatic cylinders over piston rods84, 85. Each slide carries tonglike parts 86, 87 and 86', 87',respectively, which are mounted to swing about pins 88 and which, at theends remote from the blow pipe 15, are provided with depressions 89.Each pair of these depressions receives a compression spring 90. Thesprings 90 urge the jaws 86, S7, 86', 87' into the position shown inFIG. 30 and tend to hold them in that position. At the ends adjacent theblow pipe 15, the jaws 86, 87, 86', 87 are provided with extensions 86a,87a, 85a 87a shaped to allow the blow pipe 15 and the fins 22 to bereceived in a central space 91. A part 92 on the slide 83, and a part 94on the slide 82, are arranged to slide in the directions of the arrowsand 81. The part 92 is shown to be provided with camming surfaces 92a,92b, and part 94 has camming surfaces 94a, 94b.

The construction of FIGS. 30 and 31 is used as follows: When the moldhas been opened and the blown bottle carried by the blow pipe is readyto be freed of waste material clinging thereto, the slides 82 and 83 aremoved toward each other until they reach the position shown in FIG. 30in which position the fins 22 are clamped between the extensions 86a,87a, 86a, 87a. Next, the parts 92 and 94 are slid in the direction ofarrows 3i and 81, respectively, until they assume the positions shown inFIG. 31. As the parts 92 and 94 make these movements, the cammingsurfaces 92a, 92b, 94a, 94b turn the jaws 86, 87, 86, 87 and swing theirouter ends into engagement, while the inner ends spread. These turningmovements of the jaws 86, 8'7, 86', 87, take place against the force ofthe compression springs 90. During these movements the fins 22 and theannular extension 23 are separated from the neck and shoulder of thebottle produced. From the drawing it is seen that the distance betweenthe corners 93 of the opposite extensions 86a, 87a, 86a, 87a decreasesas the position of FIG. 30 changes to the position of FIG. 31, at leastat the beginning of the change, which decrease increases the clampingpressure exerted upon the fins 22. To ease the removal of the annularextension 23 the latter is formed with two notches 31, as has beenexplained in the description of FIGS. 28 and 29.

Upon separation of the waste material, the slides 82, 83 are moved inthe direction of the arrows 8t 81 back into their starting positions,whereby, due to the return movement of the slides 92 and 94 in thedirection of the arrows 81 and 80, respectively, the jaws 86, 87, 36',87 are made to swing back into their starting positions by the springs90.

It is also possible to control in a positive manner the movements of asingle pair of jaws only rather than the movements of both pairs ofjaws. For instance, I provide the slide 92 with its camming surfaces 92aand 92b but omit the slide 94 with camming surfaces 94a, 9419. When theextensions 86a, 87a of the jaws 86, 87 of the slide 83 are pressedagainst the fins 22 and the annular extension 23 and thus also againstthe extensions 86a, 87a of the jaws 86, 87', the fins 22 and the annularextension, as well as the jaws 86', 87' of the slide 82, are compelledto take part on the movements of the jaws 86, 87 of the slide 83, asthis is shown in FIG. 31.

In the constructions of FIGS. 1 to 27, the waste-separating device ofFIGS. 30 and 31 may, just as the device of FIGS. 28 and 29, take theplace of the device 25.

It has already been shown, with respect to FIGS. 1 t0 6, 22 to 24, 25 to27, how waste material on the bottom of a freshly blown bottle may beremoved. FIGS. 32 to 34 deal with a construction designed to remove suchwaste in another manner. The removal according to FIGS. 32 to 34contitutes a modification of the removal according to FIGS. 1 to 6 and22 to 24. FIG. 32 represents a condition in the sequence of events whichoccurs a little later than the condition illustrated in FIG. 1 Thegrasping l 1 device 13a has lowered the severed tube length 12 into thespace between the open mold sections 14, 14. The leading end of the tubelength 12 is shown to pass over the blow pipe 15 which enters into theopen mold space from opposite, and in alignment with, the extrusiondirection. Upon the closing of the mold over the tube 12, there remainswaste material which extends between the grasping device and the top ofthe mold. The top of the mold is shown to form the bottom of the bottle.The waste material 1.2.2 will be torn off as the grasping device movesin the direction of the arrow 95. Thus, as distinguished from thevertical upward movement of the grasping device of FIGS. 1 to 6 and 22to 24, the grasping device 13a is laterally moved, as in the case ofFIGS. 25 to 27, but after the lateral movement, it is moved upwardly inthe direction of the arrow 95, provided the grasping or gripping deviceis to be used as severing device as well. The gripping device is openedeither during the horizontal or vertical movement so that the wastematerial torn oil and taken along by the device may be dropped in thedirection of the arrow 96 into a collecting container. The constructionand use of the construction of FIGS. 32 to 34 proves useful when thesevered tube length to be introduced in a mold is transported from anextrusion nozzle horizontally rather than vertically. A vertical leg ofthe movement of the gripping device may be altogether dispenscd with ifthe severed tube ength is moved across the parting plane of the moldused. In such a case, the gripping device may be arranged somewhat abovethe mold, at a level that will ensure the tearing off of the wastematerial from the bottom of the bottle. The gripping device performs ahorizontal reciprocatory movement. The tearing off is done as shown, forinstance, in FIGS. and 31.

So far, it has been assumed that blow pipe and the bottle supported bythe blow pipe are stationary and that the waste-separating device 25,25', 25"; 25 25 76a 79b; 75a, 75b, 76a, 76b; 86, 3'7, 86', 87,respectively, after the fins 22 and the annular extension 23 have beengrasped, are moved relative to blow pipe and bottle. However, it will beappreciated that it is within the scope of the invention, as has alreadybeen indicated, to provide a waste-separating device which upon theclosing movement of the cooperating parts Will stand still while thebottle is moved relative to the waste-separating device.

It is believed that the method of my invention as well as theconstruction and operation of the forms of apparatus for practicing theinvention, as shown, and the many advantages thereof will be understoodfrom the foregoing detailed description. Some of the features andadvantages are reviewed hereinafter.

Essentially, the invention provides mechanicaly stripping freshly blownplastic articles from waste material adhering thereto. The article, assoon as sufiiciently solidified, and a waste-stripping device arerelatively moved past each other. This stripping or waste-removingdevice acts upon waste that projects beyond the profile of the article.If there is waste that projects in more than one place, thewasteremoving device or devices have to be formed accordingly to actupon all the Waste that projects beyond the profile of the article.Thus, waste may be removed mechanically in one place only or in morethan one place or in all places of occurrence. If there are more than asingle waste-removing device, they may be operated in dependence fromeach other or independently. The relative movement of article andwasteremoving device is ordinarily either perpendicular to or across theparting surface of the mold used. In case of perpendicular movement itis necessary first to move the article away from the open mold space,after opening the mold, so that the following abutting and relativemovements of article and waste-removing device will not interfere withthe open mold sections. This can be done by moving either the article orthe mold. If the relative movement is across the parting surface of thet2 mold, no movement prior to the abutting and relative movements may beneeded. H65. 17 and 18 show a turning of the article about its axisthrough prior to the abutting and relative movements, and FIGS. 19 and20 show a rotatory movement of the article prior to the abutting andrelative movements.

The blown article is preferably supported by a blow pipe, while beingmoved or standing still. The blow pipe is advantageously used to carrythe blown article near the waste-removing device. As has been stated, ifthe abutting and relative movements of article and waste-removing deviceare perpendicular to the parting plane of the mold, the blow pipe, whilesupporting the blown article, is moved out of reach of the mold, or themold is moved away, so that the following abutting and relativemovements may take place. If the abutting and relative movements areacross the parting plane of the mold, the blow pipe may, for instance,turn about its axis through 90 or swing about an end thereof.

The waste-removing device of the invention consists essentially of twocooperating parts. These parts are moved against the plastic Waste onopposite sides thereof and preferably clamp the waste between them andthus separate the waste from the article, when being relatively movedwith respect to the article. The two parts may be formed differently,for instance, tong-like.

With waste that circularly adheres to the article, the inventionprovides notching such waste in one or two places, during the formationof the article, which allows the waste to split and to be easilyremoved. A single notch is preferably provided at a place remote fromthe position assumed by the transferred waste material.

It will be apparent that the present invention is not restricted to theuse of tubular shapes to start with. Instead, the invention isapplicable to preforms of any other shape, for instance, sheets, etc.Nor is the invention restricted to the extrusion of tubing directly intothe space of an open mold. Tubes and other preforms may be workedaccording to this invention even though they are moved into an open moldspace by means of a gripping device or by other means from places otherthan above the mold.

It will further be apparent that while I have shown and described myinvention in a few forms only, many changes and modifications may bemade without departing from the spirit of the invention defined in theappended claims.

I claim:

1. A process for the manufacture of hollow articles from plastics byblowing, using a sectional mold, blow pipe means, and means for tearingoft" flashing, com prising introducing at least a single preform of theplastic material used, in condition of plasticity, into the open spacebetween the sections of said mold, closing said mold about at least asingle segment of said preform, the closed mold having at least a singlecomposite cavity conforming in shape to the article to be produced,admitting a fluid pressure medium to the mold-enclosed segment throughsaid blow pipe means, thus expanding said segment into molding contactwith the wall defining said mold cavity, and forming a blown articlehaving flashing adhering thereto and being supported by said blow pipemeans, opening said mold, withdrawing from said mold said blow pipemeans with said blown article thereon, positioning stid blown articleand said flashingtcaring means to be relatively movable along a straightpath, grasping the flashing in the flashing-tearing means on oppositesides of the blow molded article, and effecting a relative straightmovement of said blown article and said flashing-tearing means, therebycausing said flashing-tearing means to tear said flashing from saidblown article.

2. A process for the manufacture of hollow articles from plastics byblowing, using a sectional mold and gripping means, comprising extrudingat least a single preform of the plastic material used, severing alength of said preform from the parent body of plastic material with theaid of said gripping means, moving said gripping means with the severedlength supported thereby to introduce said length, while still incondition of plasticity, into the open space of said mold, leaving saidgripping means outside the mold sections to be closed, closing said moldabout a segment of said severed length, there by pinching said segmentadjacent said gripping means, admitting a fluid pressure medium to themold-enclosed segment, forming a blown article having flashing adheringthereto, causing said gripping means to hold a portion of flashingformed between said mold and gripping means, moving said gripping meansand said portion of flashing away from said mold, thereby tearing saidportion of flashing from said blown article while holding said blownarticle within said mold.

3. An apparatus for the manufacture of hollow articles from plastics byblowing, comprising a mold including opposing sections to be closed andopened, blow pipe means to admit a fluid pressure medium to aninflatable embryo product within the closed mold and thus to expand saidembryo product to the article to be produced, the expanded or blownarticle having two formations of flashing adhering thereto, saidformations projecting from said article in opposite directions,flashing-tearing means, means to close and open said mold, means toWithdraw from the open mold said blow pipe means and said blown articlethereon, means for positioning the withdrawn arti cle and saidflashing-tearing means to be relatively movable along a straight path,and means for effecting said relative movement, said flashing-tearingmeans including opposing parts provided with faces, said means forposition-and effecting said relative movement being adapted to placesaid faces in grasping condition with respect to opposite sides of saidformations and to tear said formations from the blown article.'

4. In the apparatus according to claim 3, a single pair of opposingmembers of forklike shape, said pair constituting said flashing-tearingmeans, each member being provided with two tines, the end faces of thetines being adapted to abut against said opposite sides and thus formingsaid grasping faces.

5. In the apparatus according to claim 4, the tines of one member ofsaid pair being longer than the tines of the other member, said meansfor performing said relative tearing movement moving said members, whilesaid two formations of flashing are sandwiched between the end faces ofthe four tines, in the direction toward the member having the shortertines.

6. In the apparatus according to claim 3, said blow pipe means includingfour blow pipes mounted in form of a cross and to be rotatable about thepoint of intersection, said mold sections, said cross of blow pipes, andsaid flashing-tearing means being mounted so as to make one of the blowpipes cooperate with said mold to be ready to carry the article lastblown into another blow pipe position while another blow pipe supportingthe previously blown article and said flashing-tearing means performsaid relative tearing movement.

7. In the apparatus according to claim 3, two units of flashing-tearingmeans, said blow pipe means including two spacedly and slidably arrangedblow pipes, said mold sections, blow pipes, and two units being mountedso as to make one of the blow pipes cooperate with the mold to be readytocarry the article last blown into another blow pipe position while theother blow pipe supporting the previously blown article and one of saidtwo units perform said relative tearing movement.

8. In the apparatus according to claim 3, means to extrude a preformtoward the space within the open mold, gripping members adapted to severa length of preform from the parent body and to transport the severedlength into said open mold space, means to close and open said grippingmembers and to relatively move said mold and gripping members toward andfrom each other.

9. In the apparatus according to claim 3, said flashing tearing meansincluding two pairs of clamping members provided with faces to engageopposite sides of said formations, said means for performing saidrelative tearing movement acting in the directions of the extent of thetwo waste formations.

10. A process for the manufacture of hollow articles from plastics byblowing, using a sectional mold, blow pipe means, and flashing-tearingmeans, comprising introducing at least a single preform of the plasticmaterial used, in condition of plasticity, into the open space betweenthe sections of said mold, closing the mold about at least a singlesegment of said preform, the closed mold having at least a singlecomposite cavity conforming in shape to the article to be produced,admitting a fluid pressure medium to the mold-enclosed segment throughsaid blow pipe means, thus expanding said segment into molding contactwith the wall defiining said mold cavity, and forming a blown articlehaving flashing adhearing thereto and being supported by said blow pipemeans, opening the mold, turning said blown article through andpositioning said blown article and said flashing-tearing means to berelatively movable across the parting plane of said mold, and to permitsaid flashing-tearing means, upon eifectuation of a relative movement ofsaid blown article and flashing-tearing means across said parting plane,to grasp said flashing, grasping said flashing in said flashing-tearingmeans, and effecting said relative movement, thereby tearing saidflashing from said article.

11. An apparatus for the manufacture of hollow articles from plastics byblowing, comprising a mold including opposing sections to be closed andopened, blow pipe means to admit a fluid pressure medium to aninflatable embryo product within the closed mold and thus to expand theembryo product to the article to be produced, the expanded articlehaving two formations of waste projecting therefrom in oppositedirections, flashing-tearing means, means to close and open said mold,means to withdraw said blow pipe means and said expanded article thereonfrom the open mold, means for positioning the withdrawn article and saidflashing-tearing means to be relatively movable along a straight path,and for permitting said flashing-tearing means, upon effectuation of arelative movement of said expanded article and said flashing-tearingmeans along a straight path, to grasp opposite sides of said twoformations, and means for effecting said relative movement, saidflashing-tearing means including two pairs of clamping members providedwith faces to be placed in abutting condition with respect to saidopposite sides, said means for performing said relative tearing movementacting in the directions of the extent of said formations, each of saidpairs being constituted by two normally aligned levers, each lever beingarranged to swing about a point intermediate the ends thereof, adjacentend faces of said levers constituting said faces and being adapted totear, when swinging, said formations of flashing from the expandedarticle.

References Cited in the file of this patent UNITED STATES PATENTS2,890,483 Soubier Jun. 16, 1959 2,943,349 Adams et al. July 5, 19602,953,814 Mumford Sept. 14, 1960 2,975,473 Hagen et al. Mar. 21, 19612,978,745 Langecker Apr. 11, 1961 2,988,776 Schaich June 20, 19612,994,103 Schaich Aug. 1, 1961 3,003,187 Schaich Oct. 10, 1961 3,009,198Kalman et al. Nov. 21, 1961

1. A PROCESS FOR THE MANUFACTORE FO HOLLOW ARTICLES FROM PLASTICS BYBLOWING, USING A SECTIONAL MOLD, BLOW PIPE MEANS, AND MEANS FOR TEARINGOFF FLASHING, COMPRISING INTRODUCING AT LEAST A SINGLE PREFORM OF THEPLASTIC MATERIAL USED, IN CONDITION OF PLASTICITY, INTO THE OPEN SPACEBETWEEN THE SECTIONS OF SAID MOLD, CLOSING SAID MOLD ABOUT AT LEAST ASINGLE SEGMENT OF SAID PREFORM, THE CLOSED MOLD HAVING AT LEAST A SINGLECOMPOSITE CAVITY CONFORMING IN SHAPE TO THE ARTICLE TO BE PRODUCED,ADMITTING A FLUID PRESSURE MEDIUM TO THE MOLD-ENCLOSED SEGMENT THROUGHSAID BLOW PIPE MEANS, THUS EXPANDING SAID SEGMENT INTO MOLDING CONTACTWITH THE WALL DEFINING SAID MOLD CAVITY, AND FORMING A BLOWN ARTICLEHAVING FLASHING ADHERING THERETO AND BEING SUPPORTED BY SAID BLOW PIPEMEANS, OPENING SAID MOLD, WITHDRAWING FROM SAID MOLD SAID BLOW PIPEMEANS WITH SAID BLOWN ARTICLE THEREON, POSITIONING STID BLOWN ARTICLEAND SAID FLASHINGTEARING MEANS TO BE RELATIVELY MOVABLE ALONG A STRAIGHTPATH, GRASPING THE FLASHING IN THE FLASHING-TEARING MEANS ON OPPOSITESIDES OF THE BLOW MOLDED ARTICLE, AND EFFECTING A RELATIVE STRAIGHTMOVEMENT OF SAID BLOWN ARTICLE AND SAID FLASHING-TEARING MEANS, THEREBYCAUSING SAID FLASHING-TEARING MENAS TO TEAR SAID FLASHING FROM SAIDBLOWN ARTICLE.